Photometric Study of Variable Stars in the Open Cluster NGC6866

TL;DR

This study identifies 19 variable stars in NGC6866, classifies their types, assesses cluster membership, and discusses the relationship between cluster properties and gamma Dor stars.

Contribution

It reports the discovery and classification of variable stars in NGC6866, including their probable cluster membership and implications for cluster properties.

Findings

19 variable stars discovered in NGC6866

Cluster membership inferred for several variables

No correlation between cluster age/metallicity and gamma Dor stars

Abstract

We report the discovery of 19 variable stars and two blue-stragglers in the field of the open cluster NGC6866. Three of the variable stars we classify as delta Sct, two, as gamma Dor, four, as WUMa, two, as ellipsoidal variables, and one, as an eclipsing binary. Seven stars show irregular variability. Two of the pulsators, a delta Sct star NGC 6866-29 and a gamma Dor star NGC6866-21, are multiperiodic. From an analysis of proper motions, we conclude that the delta Sct stars, one of the gamma Dor stars and both blue-stragglers are very probable members of the cluster. The position on the color-magnitude diagram of seven other variables suggests that they also belong to the cluster. The eclipsing binary, which we discover to be a new high-velocity star, and the seven irregular variables are non-members. Then, we discuss in detail the age and metallicity of open clusters that host gamma Dor stars and we show that none of these parameters is correlated with the number of gamma Dor stars in cluster.